AKT · Dermatology/Benign lesionslow yield

Lipoma

Benign tumour of mature adipocytes

Overview

A benign tumour of mature fat — the commonest soft-tissue tumour. A soft, mobile, painless subcutaneous lump that "slips" under the fingers. Reassurance is usually all that is needed.

Recognise

Soft, smooth, mobile, painless subcutaneous nodule with a characteristic doughy/"slip" feel
Common on the trunk, shoulders, neck and limbs; slow-growing
Multiple lipomas may be familial (familial multiple lipomatosis); a tender variant = angiolipoma

Red flags

Rapid growth, size >5 cm, fixation, pain, or deep/retroperitoneal location → exclude liposarcoma (imaging ± biopsy)

Differentials & how to tell them apart

Epidermoid cysthas a central punctum, discharges keratin, more superficial

Liposarcomalarge, deep, fixed, rapidly growing or painful — needs imaging/biopsy

Abscessred, hot, tender, fluctuant

Clinical image

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Lipoma — clinical imagesDermNet

Investigations

Clinical. Ultrasound/MRI ± biopsy if large (>5 cm), rapidly growing, fixed, or painful (to exclude liposarcoma).

Management

Reassurance; excision only if symptomatic or red-flag features

1Reassure for a typical soft, mobile, painless small lipoma.Gate: A lump that is large (>5 cm), deep, fixed, rapidly growing or painful is NOT a simple lipoma → image (MRI) and consider biopsy to exclude liposarcoma
2Excise for symptoms, cosmesis or diagnostic uncertainty.

Reassurance — most lipomas need no treatment

Excision — for symptoms, cosmesis, diagnostic doubt, or red-flag features

Key points

The soft, mobile, slip-sign lump is reassuringly benign. The red flags (size, depth, fixation, pain, rapid growth) are what separate it from liposarcoma.

Monitor & prognosis

Stability; review red-flag change.

Benign.

Source: NICE CKS Lipoma; StatPearls